1. Any school district which makes provision for transporting pupils as provided in section 162.621 and sections 167.231 and 167.241 shall receive state aid for the ensuing year for such transportation on the basis of the cost of pupil transportation services provided the current year. A district shall receive, pursuant to section 163.031, an amount not greater than seventy-five percent of the allowable costs of providing pupil transportation services to and from school and to and from public accredited vocational courses, and shall not receive an amount per pupil greater than one hundred twenty-five percent of the state average approved cost per pupil transported the second preceding school year, except when the state board of education determines that sufficient circumstances exist to authorize amounts in excess of the one hundred twenty-five percent of the state average approved cost per pupil transported the second previous year.

2. The state board of education shall determine public school district route approval procedures to be used by each public school district board of education to approve all bus routes or portions of routes and determine the total miles each public school district needs for safe and cost-efficient transportation of the pupils and the state board of education shall determine allowable costs. No state aid shall be paid for the costs of transporting pupils living less than one mile from the school. However, if the state board of education determines that circumstances exist where no appreciable additional expenses are incurred in transporting pupils living less than one mile from school, such pupils may be transported without increasing or diminishing the district’s entitlement to state aid for transportation.

3. State aid for transporting handicapped and severely handicapped students attending classes within the school district or in a nearby district under a contractual arrangement shall be paid in accordance with the provisions of section 163.031 and an amount equal to seventy-five percent of the additional cost of transporting handicapped and severely handicapped students above the average per pupil cost of transporting all students of the district shall be apportioned pursuant to section 163.031 where such special transportation is approved in advance by the department of elementary and secondary education. State aid for transportation of handicapped and severely handicapped children in a special school district shall be seventy-five percent of allowable costs as determined by the state board of education which may for sufficient reason authorize amounts in excess of one hundred twenty-five percent of the state average approved cost per pupil transported the second previous year. In no event shall state transportation aid exceed seventy-five percent of the total allowable cost of transporting all pupils eligible to be transported; provided that no district shall receive reduced reimbursement for costs of transportation of handicapped and severely handicapped children based upon inefficiency.

4. No state transportation aid received pursuant to section 163.031 shall be used to purchase any school bus manufactured prior to April 1, 1977, that does not meet the federal motor vehicle safety standards.